Cement retainer



Jun 3, 1947. v

Filed Aug. 9, 1945 E "20 42 a 13;? 6 r'l'l l7 5 I I zz/ I Z I a i 6INVENTORS MILO 0. WILSON BY v. D. DAVIDSON mam.

HTTO/PNEV.

Patented June 3, 1947 CEMENT RETAINER.

Milo C. Wilson and Vernon D. Davidson, Corpus Christi, Tex.;. saidWilson assignor to said Davidson Application August 9', 1943, ,SerialNo.d97g936 1 Claim.

The invention relates to a tool for retaining, liquid under pressure inan oil. well. In applying liquids under pressure in an oil- Well, it isnecessary that a tool be provided which can be securely anchored inposition so as to remain stationary when pressure is applied below it inorder to force liquids into the earth formations or to accomplish otherfunctions.

The present invention is in the nature of an improvement over thatdisclosed in Patent 2,338,- 370'which. Wasgranted to one of the presentjoint inventors.

With the present. cement retainer the structure has been so devised thatthe anchoring mechanism to hold the retainer ina set position isactuated as a function of the pressure being applied to the tool so thatthe tendency to anchor the tool increases with the pressure applied toit.

It is one of the objects, of the invention. to pro.- vide a cementretainer to be anchored in a well bore wherein the hydraulic pressurebeing applied through the retainer tool reacts in the tool to anchor thetool.

Another object of the invention is to provide in a cement retainer a setof slips and a wedging mandrel wherein the mandrel is urged to wed'gingposition by the hydraulic pressure being exerted through the tool,

Another object of the invention is to provide a cement retainer having amandrel with a, slip supporting housing telescoped thereabout whereinthe slips will be set when the. mandrel and housing are urged apart.

Another object of the invention is toprovide a cement retainer whereinamandrel and-slip supporting, housing are urged apart to set the slipsby the hydraulic pressure applied through the retainer.

Other and further objects of the invention will be readily apparent whenthe following description is considered in connection with theaccompanying drawings wherein:

Fig. 1 is a vertical sectional view of the retainer tool with the slipsin retracted position.

Fig. 2 is a section taken on the line 2--2 of Fig. 1 and illustratingthe arrangements of the slips and the friction drag springs.

Fig. 3 is a vertical sectional view of the retainer in set position in awell pipe.

Fig. 4 is a side elevation of the cement retainer.

The retainer is made up of a mandrel 2 which is connected to anoperating pipe 3 by which .the tool may be manipulated in the well bore.This mandrel 2 has an open passage 4 there through and is provided onits outer periphery with the frustoeconical wedge portion 5. Ascoondsuch portion .6 is disposed below the first portion. The portion 6 iscut away at l to provide thehshank. or tail piece 8 of the mandrel. Thistail piece terminates in. an exposed end area 9 and has a plurality ofpacking or sealing. rings [0 afiixed about its periphery by having. themdisposed inthe annular recesses ll about the shank 8. These paekings aredownwardly facing to, seal against pressure moving upwardly thereagainstas seen. in Fig. 1.

Telescoped about the mandrel and thetail piece .8 is a. housing [5 whichcarries a, pin l6 arranged to be disposed in the, groove or slot [-1 inthe.

periphery of the mandrel. This slot [.1 as seen.

in Fig. 4. is, generally known as an inverted J slot or bayonet joint.whereby the housing and mandrel are locked together when the pin is inthe position of Fig. 4., but may have relative longitudinal movementwhen the pin is in the verticalportion of this slot. as seen in Fig. 3.In order to. manipulate the tool and move the pin [6 to either retain orrelease the mandrel relative to the. housing a plurality of drag springsl 9 are car-. ried by the periphery of the housing as seen in Figs. land2.. InFig. 3 these springs are shown as pressing against the inside ofthe well pipe 20 so asto tend to hold the housingin any position. whichit. might. be in such pipe,

The housing has a plurality of openings 2,1.

therein, each of which receives one of the slip members 22 which is.arranged for radial movement, and,- out. of the opening 2| so. that theteeth .23 on the slip may enga e the pip 0 a seen in. Fig. 3.. Theseslips are inserted through. the opening and retained inplace by a latchbar 24 attached to the outside of the housing.

Each of the slips 22 has an inclined face 26 on the back side thereofwhich is complementary with the frusto-conical surface 5 on the mandrel2 so that relative longitudinal movement by the mandrel on the one handand the housing [5 and slips on the other hand causes the slips to moveradially. If this movement of the mandrel and the housing is in adirection so that the mandrel and housing move apart, then the slipswill be set "and when they move toward each other, the slips will beretracted. If the slips become lodged in the opening or against thecasing, then the shoulder 28 on the mandrel may engage the upper end 29of the slip member and knock it loose from its gripping position or theoutstanding flange at the top of the mandrel may be so constructed as tostrike the upper end of the housing [5 to accompllsh the same purpose.The tail piece 3|]- on the 3 slips tends to hold them in positionagainst excessive outward movement.

The tool will be lowered into the well bore with the parts shown in theposition of Fig. 1. The springs l9 tend to hold the housing in anyparticular position and a slight rotation thus releases the pin I6 so asto move it into the vertical portion of the slot 17. The operating pipe3 will now be manipulated to pull upwardly on the mandrel so as to movethe wedge portions in behind the slips 2| and set them against the pipe,In this manner the cement retainer is initially anchored.

The housing l has a passage 30 therethrough which is enlarged by thetapered shoulder, 3| to provide a pressure chamber 32 which, as seen inthe drawings, receives the bottom or tail piece 8 of the mandrel withthe packings illengaging against the surface of the chamber 32 so as toform a seal therewith. The outer surface-of the lower position of thehousing l5 may be provided with a plurality of rubber cups or packings35 which are held in position by the retainer collars 3B and the spacerrings3'l, all of which are in turn 'clampedin place by the coupling 38.The contact surface of the upper collar with the shoulder of the housingmay be semi-circular faces which are ground to insure a seal to preventleakage past thepacking cups. ;A length of pipe 39 may. extend below thecoupling if desired.

, With the parts in the position of Fig. 3, cement or other liquid ispumped downwardly through the operating pipe and into the well oragainst the formation as the case may be. This pressure moves backinside of the pipe 29 and expands the packings 35 to form a seal withthe pipe. There is, of course, a tendency of this pressure to move thehousing upwardly but the initial upward pull on the operating pipe 3 andmandrel 2 maintains the slips 2| in gripping position due to thetremendous mechanical advantage of the wedge portions on the slips andthe mandrel.

In the present retainer, however, it is desired that the initialgripping'action of the slips be augmented as a function of the pressureapplied to the tool. In other words, a. semi-mechanical hydraulicoperation is obtained.

When the pressure is exerted through the pipe 3 the passage 4 of themandrel and the passage 30 in the housing, it seems obvious that thispressure will also be exerted in the chamber 32 and inasmuch ashydraulic pressure is equal in all directions there will be exerted onthe lower end 9 of the mandrel a pressure tending to expel the mandrelfrom the chamber 32 and there will be a pressure against the beveledsurface 3| in the housing tending to move the housing away from themandrel. These two opposite pressures will be equal as to any unit areaand will tend to move the mandrel and the housing apart so that therewill be a tendency due to the application of this pressure against thelower end of the mandrel to expel the mandrel and move it away from thehousing This force tends to hold the mandrel beneath the slips and tomaintain them in gripping position and of course this force will vary inaccordance with the applied pressure so that it may be said that theretainer operates as a function of the applied pressure.

In the housing I5 the enlarged recesses 4| proi vide ample area formovement of the wedge portions so that they will not become stuck due tothe. entry of sand or other foreign matter. A

' space M is 'al'so'provided by the chamber 32 being somewhat larger indiameter than the shank 8 of the-mandrelso as to avoid sticking of theparts.

Broadly the invention contemplates a semimechanical hydraulicallyoperable cement retainer which is anchored in position as a function ofthe pressure applied to it.

What is claimed is:

A cementing tool comprising an operating pipe, an open hollow mandrelthereon, a housing about said mandrel, a latch means connecting saidhousing and mandrel and operable. to permit movement of said mandrelrelative to said housing, a set of upwardly facing tapered faces on saidmandrel, a set of slips carried by saidhous- ,ing, tapered faces on saidslips to cooperate with ,said mandrel faces whereby to move said slipsinto anchoring position by upward movement of said mandrel relative tosaid housing and slips to anchor the tool in the well, packer means onsaid housing to effect a seal therearound upon application of pressurethrough said mandrel, and means on said mandrel to engage said housingupon relative downward movement so as to knock said housing and slipsloose from. anchoring position; wherein there is an enlarged chamber insaid housing and said hollow mandrel is disposed as a piston in saidchamber, there being opposed faces in said chamber.

MILO C. WILSON.

VERNON D. DAVIDSON.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS 7 Date

